1. Field of the Invention
The present invention relates to a flip chip mounting system for manufacturing relatively small products such as CSPs (Chip Size Package) or MCMs (Multi Chip Module), and more particularly to a substrate supply method, a substrate supply apparatus and a chip supply apparatus in such a chip mounting system, and a chip mounting system including those apparatuses.
2. Description of the Related Art
A conventional flip chip mounting system for manufacturing CSPs or MCMs with a configuration shown in FIG. 1 and FIG. 2 is known, for example. The flip chip mounting system (hereinafter referred to as “chip mounting system”) includes a substrate supply apparatus for supplying substrates, a chip supply apparatus for supplying chips and a flip chip mounting apparatus for mounting chips supplied by the chip supply apparatus on a substrate supplied by the substrate supply apparatus.
The substrate supply apparatus is configured to carry a substrate supplied from substrate magazine 1 by substrate conveyor 2 and to receive the substrate at a conveyor (not shown) provided on stage 3. Stage 3 includes an XY axis driving mechanism movable in a range shown as A in FIG. 1 to allow stage 3 to move to a position where the substrate can be received or released. The received substrate is carried to a predetermined position on stage 3 by the conveyor of stage 3, and then is absorbed and fixed to stage 3 with the decent of the conveyer.
In a conventional chip mounting system, a substrate for multiple devices consisting of multiple discrete substrates is used. To deal with such a substrate for multiple devices, the chip mounting apparatus is configured to absorb the entire substrate for multiple devices with stage 3 such that chips can be mounted all over the substrate for multiple devices except the area to be discarded.
Specifically, as shown in FIG. 3, chip mounting head 17 (described later) and/or stage 3 are configured to be movable to allow the relative movement of chip mounting head 17 within a mounting area including the entire surface of substrate M for multiple devices.
A chip supply apparatus generally employs chip tray holder 5 shown in FIG. 4 or a holder (not shown) similar to holder 5. For example, four chip trays 6 are disposed on chip tray holder 5 shown in FIG. 4. In order to supply chips to the chip mounting apparatus, chip tray holders 5 are accommodated in substrate magazine 1 shown in FIG. 1 and FIG. 2, and chip tray holders 5 are fed one by one with a movable stage to a position where chip transport head 7 can pick up a chip, or each holder is provided with a movable stage to transport that holder to a position where a chip can be picked up.
Now, description is made for a procedure of mounting a chip with such a chip mounting system. First, chip pickup head 8 picks up a chip from chip tray holder 5 and passes the picked chip to chip transport head 7. Chip transport head 7 passes the received chip to chip mounting head 17 (see FIG. 2). During the movement for passing the chip, carried-chip recognizing camera 9 measures the positional relationship between chip transport head 7 and the chip. Chip mounting head 17 receives the chip after it corrects displacements of the chip based on the positional relationship measured by carried-chip recognizing camera 9 with an XY θ axis provided on the head side.
Subsequently, chip/substrate recognizing camera 10 recognizes the chip absorbed and held by chip mounting head 17 and a substrate on stage 3, and an amount of positional correction is measured. Then, displacements are corrected with the high-precision XY θ axis provided on the side of chip mounting head 17, and the chip is mounted on one of discrete substrates in the substrate. After chips are mounted on all the discrete substrates in the substrate, the substrate is taken out to complete the sequential operations.
The aforementioned conventional chip mounting system has problems as described below.
Since the substrate supply apparatus is designated to deal with a substrate for multiple devices, the chip mounting apparatus is configured such that stage 3 absorbs the entire substrate for multiple devices to allow chips to be mounted all over the substrate for multiple devices except the area to be discarded. Thus, it is necessary for chip mounting head 17 or stage 3 to have a movable axis stroke corresponding to at least the mounting area of the substrate.
Such a large movable axis stroke, however, involves an increase in size of an XY stage. As a result, the substrate supply apparatus and thus the chip mounting system equipped with the substrate supply apparatus are inevitably increased in size. In addition, since high precision becomes more difficult to achieve as the stroke is greater, flip chip mounting for which highly precise alignment is requisite needs a considerably expensive XY stage for providing higher precision.
The aforementioned chip tray holder 5 necessarily has a large area due to four chip trays 6 disposed thereon. The use of chip tray holder 5 with a large area requires not only a movable axis in the chip supply apparatus for transporting a chip to a chip pickup section but only a large movable stroke corresponding to chip tray holder 5. To provide such a large movable stroke, the apparatus itself is inevitably increased in size, and the apparatus becomes expensive. Also, when a number of types of devices are handled, it is necessary to provide an increased amount of occupied space and an increased number of movable axis strokes in proportion to the number of the types.
In bare chip assembly operation, a clean room is used for the purpose of preventing dust from affecting products since dust, motes, dirt and the like have influence on manufacturing yields. Thus, the conventional chip mounting apparatus typically uses materials or parts which may generate no dirt or dust in consideration of cleaning assuming that it is installed and used in the clean room.
The chip mounting system emphasizing the consideration of the cleaning itself generates no dirt or dust, but cannot remove motes present in the atmosphere. Thus, such an apparatus need be installed in a facility such as a clean room where the degree of cleanness is managed. Therefore, the construction of a chip mounting line involves a problem of an extremely high cost for constructing a facility such as a clean room and a problem of high running costs thereof.